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Trees: Is This a Binary Search Tree?

  • Fantoxicated + 0 comments

    I used the same approach, using the inorder traversal. But in my case I've used an instance of a class for storing the last value. Is it a good practise to do this?

    class staticVar:
    last = None

variable = staticVar()

def checkBST(root):
    if root != None:
        if not checkBST(root.left):
            return False

        if variable.last != None and variable.last.data >= root.data:
            return False

        variable.last = root
        return checkBST(root.right)
        
    return True